TL;DR -- Lass route saves 17 seconds when you have good HP for Lass (it's too messy to calculate at bad HP). Rocket route saves 30.5 seconds at all HPs, so Rocket route is better. Welcome to 2014. 

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ROUTE 3 LASS ROUTE
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Benefits:
- skip route 3 center (~16s)
- one fewer S&Q (20s)
- skip encounter/paras kill (~12s)
- skip nerd (48s)
- can red bar paras catch (~1s)
- L16 rocket (~11s)
- L16 rocket risk (~2s)
- L19 caterpie (0.5s)
- L20 ekans (1s)
- better red bar level-ups (-2.5s)
- 70 special for golbat (1s)
TOTAL: -115.0s

Costs:
- route 3 lass minus faster BC3 (~42s)
- kill route 3 encounter (~17.5s)
- moon candy scroll (0.4s)
- early dig rocket (~19s)
- L24 goldeen (~0.5s)
- L26 raticate (~0.5s)
- 1 extra input to teach BB (0.1s)
- L27 voltorb (~4.5s)
- L28 venonat (~1s)
- L29 oddish (~7.5s)
- L29 bulbasaur (~1s)
- L30 growlithe (~1s)
- L33 raticate (~1s)
- other very minor levels (~1.5s)
- uses more potions (~0.5s)
TOTAL: +98.0

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L14 ROCKET ROUTE
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Benefits:
- skip route 3 center (~16s)
- one fewer S&Q (20s)
- skip paras kill (~12s)
- skip nerd (48s)
- can red bar paras catch (~1s)
- better red bar level-ups (-2.5s)
TOTAL: -99.5s

Costs:
- use 1-2 potions before rocket (~7.5s)
- horn attack pp conservation (~5s)
- L14 rocket (~8s)
- L14 rocket risk (~5.5s)
- moon candy scroll (0.4s)
- 46 Attack for L14 Pidgey (1s)
- 46 Attack for L14 Ekans (1s)
- L19 zubat (~1s)
- L20 zubat (~0.5s)
- early dig rocket (~19s)
- L24 goldeen (~1s)
- 1 extra input to teach BB (0.1s)
- L27 voltorb (~2.5s)
- L27 voltorb risk (~2s)
- L28 venonat (~1s)
- L28 venonat risk (~0.5s)
- L29 oddish (~3s)
- L29 oddish risk (~4.5s)
- L29 bulbasaur (~0.5s)
- L29 bulbasaur risk (~0.5s)
- L30 growlithe (~0.5s)
- L30 growlithe risk (~0.5s)
- L33 raticate (~1s)
- other very minor levels (~1.5s)
- uses even more potions (~1s)
TOTAL: +69s